Power Plant and Fuel System Practice Exam

Proximate analysis breaks coal into four parts to describe how it behaves in combustion: moisture, volatile matter, fixed carbon, and ash. Moisture is the water present in the coal as received, which lowers the heat you get from burning. Volatile matter are the gases released when coal is heated in the absence of air; these volatiles drive ignition, flame development, and early burn. Fixed carbon is what remains to burn after the volatiles are driven off and moisture is removed; it’s typically found by subtracting the other components from the total. Ash is the inorganic residue left after complete combustion; it doesn’t burn but affects furnace performance and slagging. All four together account for the coal’s mass and give essential insight into its combustion behavior, making the option listing these components the best description of proximate analysis.